Method and device for sorting fluorescent lamps

ABSTRACT

A method and a device for sorting, in terms of phosphor blends, fluorescent lamps, which have a cylindrical body with a right-hand and left-hand end and with a symbol overprint. The fluorescent lamps that are conveyed into an inspection station which have a stop for defining an inspection plane, against which the lamp body respectively to be examined bears. A camera to which an image processing system is connected is directed onto the symbol overprint of the lamp body respectively to be examined. A rotating device in the inspection station is started up in order to rotate the lamp body respectively to be examined. The camera outputs pixel signals to the image processing system, which obtains image data from the pixel signals. The image processing system contains image memories with data for input symbols, and an image-comparing device which correlates the image data with the input symbol data. The respectively examined fluorescent lamp is conveyed out of the inspection station and directed into one of a plurality of sorting cracks via a switching system.

CROSS-REFERENCES TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

The invention relates to a method and a device for sorting fluorescentlamps in terms of phosphor blends.

It is important to recover the phosphor when recycling fluorescentlamps. However, the various manufacturers of fluorescent lamps usedifferent additives to the basic phosphor, and this renders the recoveryof the basic phosphor extremely difficult.

In order to avoid these difficulties, the inventor has developed aconcept of desiring to recover not the phosphor as such, but thephosphor blends as they occur in the various types of lamp of thevarious manufacturers.

SUMMARY OF THE INVENTION

It is therefore the object of the invention to create a method anddevice for sorting fluorescent lamps which are such as to permit sortingin terms of phosphor blends.

The object set is achieved on the basis of the following method steps:

a) providing an inspection station with an image processing systemhaving an image memory for recording symbol data relating to symbolimprints from different manufacturers, the image processing system alsohaving a converter for converting pixel signals into actual image dataand for comparing the actual image data with the recorded symbol data;

b) conveying the lamps into the inspection station having a stop fordefining an inspection plane, each lamp body to be examined engaging theinspection plane;

c) directing at least one camera to which the image processing system isconnected onto an assigned of of the right-hand and left-hand end ofeach lamp body to be examined with the symbol imprint thereon;

d) rotating each lamp body to be examined in the inspection stationwhile the camera is directed onto the symbol imprint;

e) outputting pixel signals from the camera to the image processingsystem and obtaining the actual image data from the pixel signals;

f) correlating the actual image data with the recorded symbol data forproducing a control signal indicative of the symbol imprint which ispresent on the lamp under inspection; and

g) conveying each inspected lamp out of the inspection station anddirecting same into one of a plurality of sorting paths via a switchingsystem which is controlled by the control signal; and

a device having the following features:

an intake conveying path for fluorescent lamps on which a stop surfacefor the lamp bodies is provided, in order to define an inspection plane,the ends of the lamp bodies remaining free from the stop surface;

a rotating device for the respectively bearing lamp body;

at least one camera, whose image plane is aligned with the inspectionplane in the region of one of the ends of the lamp body;

an image processing system which is connected to the at least one camerain order to obtain image data from pixel signals and which, furthermore,contains image memories with data for input symbols and has an imageprocessing device which correlates the image data with the input symboldata; and

an outlet conveying path with a controllable switching system which isconnected to the inspection station and can be controlled by the imageprocessing systems and is defined and further developed by the furthermeasures of the invention.

In detail, the fluorescent lamps to be sorted are fed to an inspectionstation such that they are at a predetermined distance from at least onecamera. Each fluorescent lamp is rotated in order to read the overprintlocated in the vicinity of the lamp foot and feed it to an imageprocessing system. The overprint generally contains a company logo witha type identification composed of letters and numerals. The imageprocessing system contains a memory for data recordal from such companylogos and type identifications, so that the respectively examinedfluorescent tube can be assigned to the manufacturer and the type oflamp by means of comparison. This renders it possible to sort thefluorescent lamps with regard to their phosphor blends.

In the case of fluorescent lamps, the overprint is always located onlyat one end in a region of approximately 80 mm width from the end of thelamp body. If used fluorescent lamps are delivered, the distribution ofthe ends with an overprint or without an overprint is arbitrary. Inorder to tackle this problem, it is possible to provide a double passthrough the detection system, a previously undetected fluorescent lampbeing rotated by 1800 before the second pass, such that its correct endpasses by the camera.

However, it is also possible to provide two cameras which are eachdirected onto an assigned end of the lamp body. In this configuration ofthe invention, one of the cameras is of movable design in order to beable to adapt to the different lengths of fluorescent tubes, which canbe of length in the region of between 350 and 1800 mm.

Use may be made for the purpose of supporting the lamps in theinspection station of two angles which are arranged at a distance fromone another and whose connecting lines together produce an aligningprism. The supporting angles are to be arranged at a satisfactorydistance from the ends of the fluorescent lamps, in order not to disturbthe image inspection by the cameras, one of the supporting angles is ofmovable configuration in order to be able to adapt to the specifiedlength range of from 350 to 1800 mm of the fluorescent lamps.

BRIEF DESCRIPTION OF THE DRAWINGS

Details of the invention are explained with the aid of the drawing, inwhich:

FIG. 1 shows a schematic overall view, and

FIG. 2 shows an enlarged detail from FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

Fluorescent lamps 1 are transported individually by a bucket conveyor 2to an intake conveying path 3 which comprises an inclined raceway. Aguiding top surface 4 ensures that the fluorescent tubes 1 arrive in aninspection station 10 in a horizontally aligned fashion. Provided in theinspection station 10 are stops 11 and 12 which are designed in thepresent case as stop angles and define a prism in conjunction with oneanother in order to hold the lamp body of the fluorescent tube 1 at adefined distance from a right-hand camera 21 or a left-hand camera 22.The prism defined by the angle stops 11 and 12 includes two mutuallyperpendicular faces of which each can be used as an inspection planeassigned to the cameras 21 or 22, respectively. In the illustratedexemplary embodiment, the stop surface 13 at a steeper angle to the rollsurface 3 is to be used as inspection plane. Consequently, the viewingdirections of the cameras 21 and 22 are aligned perpendicularly to thisplane 13, and the distance of the cameras is selected such that theplane 13 is sharply imaged in the camera.

Assigned to each stop angle 11 or 12 are pairs of rolls 15 and 16,respectively, which are arranged at a tangent to the stop plane 13, asis best illustrated in FIG. 2. The rolls 15 or 16 is respectivelyassigned a friction roll drive 17 or 18, in order to drive therespective roll 15 or 16, and thus to rotate the lamp body 1 located inthe inspection station.

The stop angle 11 and the assigned rolls 15 are 30 arranged in astationary fashion, while the stop angle 12 together with its rolls 16can be moved in the direction in which the inspection station 10extends, as is indicated by the double arrow 19. The displacement of thestop angle 12 together with the rolls 16 can be performed by means of aspindle and a guide, this not being illustrated for reasons of clarity.

In the same way as the stop angle 12 can be displaced, the camera 22 canalso be displaced parallel to the longitudinal extent of the inspectionstation 10, as is indicated by the arrow 23. A spindle and guide can beused for this purpose; other means of displacement can also be used. Thedisplacement of the stop angle 12 and the camera 22 allows the device tobe adapted to changing lengths of the lamp bodies 1. When the device isdesigned for a maximum length of the lamp bodies 1 of 1800 mm, the stopangle 11 is located at a distance of approximately 150 mm from the endof the lamp body 1. The movable stop angle 12 can be moved up to 15 adistance of 150 mm from the end of the lamp body 1. If shorter lamps arepresent for checking, the movable stop angle is moved to the right inthe drawing, in order to leave free approximately 150 mm to the end ofthe lamp body. The camera 21 is arranged in a stationary fashion andaligned with an end region of the lamp body 1 which is of width 80 mmand on which the manufacturer's overprint with manufacturer's symbol andtype identification is to be expected. The movable camera 22 is directedonto the respective end of the lamp body 1, specifically onto a regionof likewise 80 mm. width.

The two cameras 21 and 22 are connected to an image processing system 30which can pick up digital image information coming from the cameras aspixel signals and compare it to stored image information. This storedimage information relates to the overprints to be expected at the end ofthe lamp body, specifically as regards manufacturer and type of lamp. Ingeneral, company symbols or logos and letter/numeral combinations areoverprinted, the size of the overprint depending on the type of lamp,when the lamp body 1 is rotated during checking, and the overprint movesthrough the visual field of the camera 21, the company logo and the typeidentification are read off in the sequence to which we are accustomed.If, by contrast, the symbol overprint is located at the left-hand end ofthe lamp body, the camera 22 reads the symbol overprint backwards. Thisis taken into account during processing in the image processing system.If the image processing system has a monitor 31 for monitoring purposes,then said monitor is fed such that the overprint appears in the correctreading direction for a person.

Connected to the image processing system 30 is a switching controller 32which ensures that the lamp body respectively checked is correctlysorted. This is performed in an outlet conveying path 24, which can bedesigned as an inclined raceway with a row of flaps 25. By reversing therolls 15 and 16, the lamp body respectively located in the inspectionstation 10 is raised above the height of the stop angle 11 and 12 andthen reaches the raceway 24 and rolls downward thereupon. Each flap 25has a flap drive which is respectively connected to the switchingcontroller 32. The switching controller 32 has as many outputs as thereare phosphor blends plus a further output for non-identified phosphorblends. The flaps 25 are assigned to the respective outputs of theswitching controller 32, such that upon the detection of a specificclass of fluorescent tubes by manufacturer and type of lamp or types oflamp, to which a specific phosphor blend is assigned, an assigned flap25 is opened and the downward rolling fluorescent tube lands in acontainer located therebelow.

The new sorting method permits relatively quick detection of the classof the fluorescent tube under examination. It is possible to contemplatecycle times from 2 seconds to 0.5 seconds. The selectivity of thedetection of the symbol overprint is very high, “symbol overprint” beingunderstood both as the company logo and as the type identification.Lamps whose classification cannot be unambiguously detected areprocessed in the previously customary way. In this way, the phosphorblends recovered from the fluorescent tubes are recovered with a qualitywhich is extremely high since it is not impaired by admixtures. Thephosphor blends are obtained from the fluorescent tubes in the usualmanner by opening the fluorescent tubes and blowing out the coating withcompressed air.

What is claimed is:
 1. A method for sorting, in terms of phosphorblends, fluorescent lamps which have a cylindrical lamp body with aright-hand and left-hand end and with a symbol imprint characteristic ofa specific manufacturer and type of lamp, comprising the steps of: a)providing an inspection station with an image processing system havingan image memory for recording symbol data relating to symbol imprintsfrom different manufacturers, said image processing system also having aconverter for converting pixel signals into actual image data and forcomparing said actual image data with said recorded symbol data; b)conveying said lamps into said inspection station having, a stop fordefining an inspection plane, each lamp body to be examined engagingsaid inspection plane; c) directing at least one camera to which saidimage processing system is connected onto an assigned one of saidright-hand and left-hand end of each lamp body to be examined with saidsymbol imprint thereon; d) rotating each lamp body to be examined in theinspection station while said camera is directed onto said symbolimprint; e) outputting pixel signals from the camera to the imageprocessing system and obtaining said actual image data from said pixelsignals; f) correlating said actual image data with said recorded symboldata for producing a control signal indicative of the symbol imprintwhich is present on the lamp under inspection; and g) conveying eachinspected lamp out of the inspection station and directing same into oneof a plurality of sorting paths via a switching system which iscontrolled by said control signal.
 2. The method as claimed in claim 1,characterized in that the fluorescent lamps are conveyed in a horizontalalignment of their bodies (1), and in that the fluorescent lamps runinto an angular prism as stop means (11, 12).
 3. A device for carryingout the method as claimed in claim 1, having the following features: anintake conveying path (3) for fluorescent lamps on which a stop surface(13) for the lamp bodies (1) is provided, in order to define aninspection plane, the ends of the lamp bodies (1) remaining free fromthe stop surface; a rotating device for the respectively bearing lampbody; at least one camera (21), whose image plane is aligned with theinspection plane (13) in the region of one of the ends of the lamp body(1); an image processing system (30) which is connected to the at leastone camera (21) in order to obtain image data from pixel signals andwhich, furthermore, contains image memories with data for input symbolsand has an image processing device which correlates the image data withthe input symbol data; and an outlet conveying path (24) with acontrollable switching system (25) which is connected to the inspectionstation (10) and can be controlled by the image processing systems (30,32).
 4. The device as claimed in claim 3, characterized in that one ofthe cameras (22) can be moved parallel to the inspection plane (13) inorder to adapt to different lengths of the lamp body (1).
 5. The deviceas claimed in claim 4, characterized in that the intake path (3) isdesigned as an inclined surface at whose lower end two stop angles (11,12) are located which are arranged at a prescribed spacing from theright-hand or left-hand end, respectively, of the lamp body (1) anddefine a prismatic body in connection with one another.
 6. The device asclaimed in claim 5, characterized in that one holding angle (11) isstationary and the other holding angle (12) can be moved along theprismatic body in order to adapt the support of the lamp body (1) todifferent lengths of the lamp body.
 7. The device as claimed in claim 4characterized in that one of the cameras (22) can be moved parallel tothe inspection plane (13) in order to adapt to the different lengths ofthe lamp body (1).
 8. The device as claimed in claim 5, characterized inthat one of the cameras (22) can be moved parallel to the inspectionplane (13) in order to adapt to the different lengths of the lamp body(1).
 9. The device as claimed in claim 6 characterized in that one ofthe cameras (22) can be moved parallel to the inspection plane (13) inorder to adapt to the different lengths of the lamp body (1).
 10. Thedevice as claimed in claim 1, characterized by moving the camera alongthe lamp body.
 11. The device as claimed in claim 1, rotating the lampby 180 degrees and reentering the lamp into the inspection station.